(a) Field of the Invention
This invention relates to the field of chemistry and more particularly, to novel mixtures which consist essentially of either a monoazo compound or of a disazo compound multiply and randomly substituted by aminomethyl moieties and to the acid-addition salt forms thereof.
(B) Description of the Prior Art
A class of organic compounds known as direct dyes are known to be useful as dyeing agents for paper and fabrics. Among this group of organic compounds there are named the water-soluble azo and disazo dyestuffs and their acid-addition salts. However, heretofore known water-soluble azo and disazo dyestuffs and their acid-addition salts have suffered from a number of deficiencies when employed as dyes for coloring cellulose in the form of bleached pulp of the type used for the manufacture of household paper goods such as paper napkins, paper toweling, facial tissues and so forth. Thus, they have been found to undesirably bleed out of paper products colored with them when the article is brought into contact with water, milk, soapy solutions or other common household solutions. They have also been found to have relatively poor substantivity to bleached pulp and have suffered from a low rate and degree of exhaust from dyeing solutions containing them. There is thus a need for water-soluble dyestuffs for coloring bleaching pulp which have high bleed resistance, good substantivity and a high rate and a high degree of exhaust from aqueous dyeing solutions in which they are utilized. It has surprisingly been found that mixtures of the instant invention consisting essentially of either a monoazo or a disazo compound into which multiple aminomethyl groups have been randomly introduced and the acid-addition salts thereof possess these desired properties and consequently are particularly well adapted as dyestuffs for bleached pulp.
The following items to date appear to constitute the most relevant prior art with regard to the instant invention.
German Pat. No. 82,626 (granted July 1, 1895) discloses basic azo dyestuffs obtained by diazotization of p-aminobenzylamine and coupling of the diazonium compound with beta-naphthol and resorcinol.
Japanese Kokai No. 74/98,833 (published Sept. 18, 1974) discloses a basic azo dyestuff obtained by diazotization of p-aminobenzylamine and coupling of the diazonium compound with 1-phenyl-3-methyl-2-pyrazolin-5-one.
U.S. Pat. No. 2,128,255 (issued Aug. 30, 1938) discloses basic azo dyestuffs containing the group --X--N-(R.sub.1)(R.sub.2) wherein X is an aliphatic radical combined with an aromatic nucleus of the dyestuff molecule either directly or by means of a non-basic bridge, and R.sub.1 and R.sub.2 may be identical or different and may be hydrogen or alkyl, cycloalkyl, hydroalkyl or aralkyl radicals or members of a saturated ring system.
(c) Prior Publication
Belgian Pat. No. 838,280, which was granted on Aug. 5, 1976, discloses a series of compounds having the formula ##STR1## wherein n is an integer whose value is one or two; R is hydrogen, lower-alkyl, lower-alkoxy or halogen; R.sup.2 is hydrogen, lower-alkyl, lower-alkoxy, halogen, aminomethyl or 2-aminomethyl with the proviso that A is other than .beta.-naphthol when R.sup.2 is aminomethyl or 2-aminoethyl; R.sup.1 and R.sup.3 are the same or different and are each hydrogen, lower-alkyl, lower-alkoxy, halogen or aminomethyl with the proviso that at least one of R.sup.1 and R.sup.3 is aminomethyl when R.sup.2 is other than aminomethyl or 2-aminomethyl; and A is an azoic coupling radical. The compounds which are prepared by coupling a diazotized aminoalkylated aniline with a coupling agent, are useful as cellulose substantive dyes. The coupling agent and hence also the A moiety arising therefrom in the products are devoid of aminoalkyl substituents. This reference appeared subsequent to applicants' invention described herein and less than one year prior to the filing date of this application.